BitLevelCOM - C source code library that allows a calling user application to access serial communication ports (COM devices) under 32-bit MS Windows operating systems. It allows to transmit and receive data and control line signals (e.g. RTS, DTR)..

Virtual Serial Port ActiveX control creates a virtual port and lets you view and control any data sent to virtual com port by other applications and respond to them by sending your own data to virtual port. Offers full software serial port emulation.

Chilkat Crypt is an advanced .NET encryption component that offers both RSA public-key encryption with digital signatures as well as symmetric encryption algorithms including AES (Rijndael), Blowfish, and Twofish. Works with C#, ASP.NET, VB.NET...